Health authorities fear there could be a measles outbreak after four people, including two children, were diagnosed with the highly infectious disease in Brisbane in the past month.
The Metro South Public Health Unit (MSPHU) has issued a warning to vaccinate and be aware of symptoms after a child was diagnosed over Easter.
MSPHU confirmed an infected child visited a Logan shopping centre on March 29 and an Arndale centre on Monday.
MSPHU Director Dr Brad McCall said four cases was above average, as usually there was only one per month.
"We are concerned there could be more," he told AAP.
"There haven't been deaths from the disease in Australia since the 90s, but we are very aware of how bad measles can be."
Mr McCall said there was no known link between the cases.
However, he urged people to get vaccinated, particularly if they were going overseas.
The measles vaccination is free for anyone born after 1966.
A warning was recently issued for commuters after a man with the disease travelled between Roma Street and Enoggera Station by train on March 19 and 20.
Another was released when a diseased person visited Currumbin Wildlife Sanctuary on March 11, a Marsden Woolworths on March 14 and Logan Hospital the next day.
Between late February and early March, an infected boy visited a Runcorn medical centre, North Lakes Westfield and Lady Cilento Children's Hospital.
Measles symptoms include fever, lethargy, runny nose, a cough and a blotchy, red rash.
Anyone who may have come into contact with an infectious person is being urged to contact their doctor.
